In the season 3 finale, Cat and Vincent are forced to work together as a couple - as never before - if they hope to defeat Liam. Liam intends to do everything he can to expose Vincent as a beast in order to destroy their love.moreless
Liam's history spurs Cat to dig into the Ellingsworth family's past; Vincent and Cat realize that they may need their secret weapon to defeat Liam; and JT develops a theory on how to save himself.moreless
Vincent agrees to help Liam retrieve evidence that could expose both of them. Cat, meanwhile, digs up disturbing information about Liam's family history.
Cat and Vincent set out to capture Liam; and come across information that could help them do just that. In other events, J.T. and Tess work to confirm that J.T. is serum-free.
Vincent, Tess and Heather try to boost Cat's spirits after the events of her big day leave her doubtful that they can defeat the threat.
It's Cat and Vincent's wedding day, and everyone is determined to make sure nothing threatens to ruin the event, including any superhuman experiments.
Using the ruse that they plan to elope, Cat and Vincent attempt to lure an unstoppable assassin out of town to protect love ones. Tired of police protection, J.T. asks Tess to help him track down a lead. Heather does her best to focus her attention on her new job.moreless
J.T. arranges a surprise bachelor party for Vincent, but the fun is cut short by a sniper who's out to end Vincent and Cat's interference with the super human experiments. In other events, Cat's family comes to town for her bridal shower and Cat visits her imprisoned father to ask for his help.moreless
Cat is assigned to a new partner; and comes to suspect that Bob and Carol are working to separate her from Vincent. In other events, JT learns that his newfound healing ability comes with a high price.moreless
Cat and Vincent see a therapist about their relationship; and Cat investigates a wealthy transplant recipient whom she suspects may be behind the mysterious experiments.
Cat and Vincent team with married DHS agents on a case; J.T. thinks he may possess super powers; Tess contemplates a career move; and Heather makes a suggestion that could make her big sister's life a little easier.moreless
Vincent moves in with Cat as the two investigate a new lead to track down who is behind the super-human experiments. While trying to impress Tess' brothers, J.T. finds out there might be side effects to the medicine Agent Thomas used to save his life. Heather returns to town with a surprise announcement.moreless
With the couple finally in a happy place, Vincent considers proposing to Catherine. But when she discovers a case involving someone turning innocent people into superhuman beings, the two have to find a way to stop them. Meanwhile, Tess is upset over J.T. stalling his recovery because of his bewilderment over how he was able to survive.moreless
Cassie goes undercover as a runway model to break up a fashion industry ring.
The Spies take on their first mission - saving a former governor, failed Presidential candidate, and current talk show host from being assassinated on the first episode of his talk show.